Organogel with Antiswelling Behavior, Environmental Resistance, and Antifrost Performance for Detecting Human Physiological Signals in Extreme Environments

Abstract

Up to now, antiswelling gels have garnered significant attention due to their applicability in amphibious environments. However, it was difficult to ensure that the gel material possessed stable antiswelling performance, mechanical properties, and electrical conductivity in extreme environments. To solve the stability issue of antiswelling gels in extreme environments, a binary solvent strategy was proposed to prepare the PCAH-W/EG organogel with ethylene glycol (EG) and deionized water (W). H-bonds formed between the −H of W and the −OH of EG, and free water in W could be converted to bound water, thus effectively improving the mechanical property and antifrost behavior of the PCAH-W/EG organogel. Chitosan (CS) worked as the first network, which could provide a stable molecular skeleton. Copolymer chains of acrylic acid (AA) and hydroxyethyl methacrylate (HEMA) worked as the second network. Hydrophilic segments of CS and AA with hydrophobic segments of HEMA reached hydrophilic–hydrophobic segment balance, endowing PCAH-W/EG organogels with antiswelling performance (balance swelling ratio was −1.008%). PEDOT:PSS as a conductive polymer imparted remarkable conductivity (0.24 S/m) to PCAH-W/EG organogels while mitigating the risk of charge leakage in underwater environments. This strategy overcame the limitations of traditional hydrogels imposed by the extreme underwater conditions. The investigation of PCAH-W/EG organogels would significantly broaden the domain of flexible wearable sensors and electronic skins.